1. Field of the Invention
The present invention relates to novel sunscreen compositions.
2. Description of the Prior Art
Sunscreen compositions are commonly used during outdoor work or leisure pursuits for protection of exposed skin against painful sunburn. Many effective sunscreen preparations are sold commercially or are described in the cosmetic or pharmaceutical literature. In general, sunscreen preparations are formulated in the form of a cream, lotion or oil containing as the active agent an ultraviolet radiation-absorbing chemical compound. The active agent acts to block the passage of erythematogenic radiation, thereby preventing its penetration into the skin.
The ideal sunscreen formulation should be nontoxic and non-irritating to skin tissue and be capable of convenient application to the skin in a uniform and continuous film. The product should be sufficiently stable chemically and physically so as to provide an acceptable shelf life upon storage. It is particularly desirable that the preparation should retain its protective effect over a prolonged period after application. Thus, the active agent when present on the skin must be resistant to chemical- or photo-degradation, to absorption through the skin and to removal by perspiration, skin oil or water. For aesthetic reasons, the product should be substantially odorless (or be capable of being scented) and be non-staining to the skin or clothing.
Many agents have been found to be effective sunscreen agents. Among the effective sunscreen agents heretofore employed are certain cinnamate esters, in particular, octyl methoxycinnamate. See, for example, U.S. Pat. Nos. 4,917,882; 5,093,109; 4,671,955 and 4,683,134.
Finely divided zinc oxide (ZnO) has also been employed as a sunscreen agent. See U.S. Patent 5,032,390 and PCT International Publication WO 92/13517. It has been suggested to combine ZnO and cinnamate esters in sunscreen compositions. See U.S. Pat. Nos. 4,917,882; 4,671,955 and 4,683,134.
U.S. Pat. No. 4,264,581 describes a sunscreen composition containing the sunscreen agents octyl dimethyl p-aminobenzoic acid ester and oxybenzone in combination with a small amount of polyethylene. The specific function of the polyethylene in the composition is not disclosed.
It is an object of the present invention to provide a novel sunscreen composition.